Electrical-impulse transmitter.



w. AITKEN.

ELECTRICAL IMPULSE TRANSMITTER.

APPLICATION FILED MAR. I7. l9l5.

r0 1 9 1 7 v 1 A M m m P L T E E H A s T E E H S 4 Egg/5,52%E5222 W. AITKEN.

' ELECTRICAL IMPULSE TRANSMITTER.

APPLICATION mm MAR. 11. 1915.

1,150,007. Patented Aug. 17, 1915.

4 SHEETS-SHEET 2.

w. AITKEN. ELECTRICAL IMPULSE TRANSMITTER.

Patented Aug. 17, 1915.

4 SHEETSSHEET 3.

APPLICATION FILED MAR. I7, 1915- W. AITKEN. ELECTRICAL IMPULSE TRANSMITTER.

4 SHEETS-SHEET 4.

ZVIJMJJQ trnrrnn stares earner ent ies.

WILLIAM AITKEN, OF.LONDON, ENGLAND, ASSIGNOR TOTHE RELAY AUTOMATIC TELEPHONE COMPANY, LIMITED.

ELECTRICAL-IMPULSE TRANSMITTER.

Specification of Letters Patent.

Patented Aug. 1%, 1915.

Application filed March 17, 1915. Serial No. 14,897.

pulse Transmitters, of which the following is a specification.

This invention relates to electrical impulse transmitters especially suitable for employment in automatic and semi-automatic telephone systems. I v

In an impulse transmitter constructed accordingto the present invention finger holds or keys are caused to act mechanically in succession upon a common member which is thus so prepared that it controls the emission of the required series of impulses.

The invention is illustrated by the accompanying drawings. v

In the machine shown a series of pins is employed projecting from the face of a Wheel in the path of an arm carried by a disk mounted co-axially with the wheel.

The wheel is rotated more or less in one direction during the selection of the pins and during this rotation the disk is connected to the wheel so that it rotates with it, and when the selection is complete and the wheel has been thus prepared the disk is released from the wheel and is returned to its normal position by a spring or other con venient means. During this return.move ment the arm is operated by the pins and transmits impulses in accordance with the pins which have been selected, and when the disk reaches its normal position it causes the release of the wheel from a catch, and the wheel itself is then brought back by a spring or other convenient means to its normal position in which the disk is again connected to it so as to be ready for a subsequent operation. All the pins normally project from the" face of the wheel and certain of them are retracted by the operating mechanism so as to leave groups projecting in their operative position, the groups being separated by spaces from which the pins have been retracted. If, for instance, it is desired to transmit impulses corresponding to the number 514 in order to establish a telephone call for a subscriber whose number is 514, the wheel is rotated through an angle corresponding to five pins, the first five pins counting from the normal position of the arm being left projecting. The wheel then rotates through an angle corresponding to say 3 pins, and these 3 pins are retracted. The wheel is then rotated 1 pin which is left protruding, then 3 pins which are retracted, then 4 pins which are left protruding, and we have thus groups of 5, l and 4 pins separated-by intervals of 3 blanks.

The disk is then released, say by lifting the telephone from its fork, and moves back emitting 5 impulses, then 1 and then 4. The wheel is rotated by a pawl engagingthese teeth and carried by a plate which can be moved through varying distancesby finger mechanism capable of being moved through varying distances. In ordinary cases there would be 10 such mechanisms numbered from 1 to 9, 0, that corresponding to I having the least movement and 0 the greatest.

Figure l is a plan of an instrument constructed in accordance with my invention and fitted with finger keys. Fig. 2 is a. sectional elevation looking to the left. Fig. 2

is a detail view of the pawl adapted to engage the ratchet wheel. Figs. 3 and ti: show alternative methods of retaining the pins.

Fig. 5 is a left hand side elevation of the wheel, and Fig. 6 is a section of the wheel, disk and clutch. Fig. 6 is a section on the line AA of Fig. 6. Fig. 6 is a perspective view of the cross piece forming part of the clutch. Fig. 6 are detail views, in perspective, showing particularly the construction and operation'of the clutch mechanism. Fig. 7 is a front view, and Fig. 8 a left hand side elevation of the pin retainer. Fig. 9 shows diagrammatically an alternative driving mechanism. Fig. 10 is an elevation of a form of finger plate for actuating the ing ring 5 which has asmall portion 6 cut away so that such of the pins 4.11s are retracted pass to the other side of the ring 5 which retains them in this retracted position as shown in Fig. 3. These pins may be looked upon as forming on the wheel a temporary record of the finger holds, recording mechanism or keys which have been actuated.

An alternative method of keeping the pins self retracted without the necessity of the ring 5 is shown in Fig. 4; the pins 4 are shouldered and as each pin is retracted by the mechanism its spring causes'the pinto move slightly outward so that the shoulder of the pin rests on the back of the wheel. One of. the pins is shown in this figure in the retracted position in which it remains until released by a slight movement toward the center of the wheel caused by its coming against a rod 4" carried by the frame. \Vhen thisoccurs the pin 4 "returns to its normal position. I

The ratchet wheel 1 ismounted loose upon a fixedaxle' .7 inside the impulse transmitter but is connected to the axle by a spiral return spring8. "The wheel can be rotated by means of a sliding pawl 9 carried by a plate 10 provided with a return spring 10*, which plate can be moved on' a suitable guide rod 11 through varying distances by the depression of finger keys. There are 10 such keys numbered 1 to 0 and capable of being depressed through Varyingdistances, the key 1 having the least depression and 0 the longest. \Vhen a key has been depressed through such a distance as will rotate the wheel 1 through an angle corresponding to the digit on the key, a pin 12 on the key engages a second plate 13 likewise provided with a return spring 13 and mounted above the plate 10. This plate 13 carries a shoulder 14 adapted to retract three pins, while at the same time the pawl 9 drives the wheel through a farther angle corresponding to 3 pins, both plates being returned to the normal position by means of their respective springs when the key is released.

It will be understood that the number of teeth on the wheel depends upon the number of digits in the highest number to be called, 13 being the maximum required for each digit, while in addition a small additional arc of the circle equal to about 6 teeth on the wheel will be required corresponding to the part 6 of the ring 5 which is cut away. Thus for a six figure call instrument a wheel of 84 teeth will berequired.

Mounted on the axle 7 by the side of the ratchet wheel 1 (Figs. 2, 6, 6f, 6? and-6) is a disk 15 which is also ponnected to the axle by a spiral spring 16. The disk carries an impulse spring jack 17 and is connected to the wheel 1 by a clutch which comprises a cross piece 18'riding on the axle and having-at each end a slot 19*so that it can be SllCl axially through a small distance. Into the slotsproject pins 20 on the disk 15 so thatthe disk rotates with the cross piece.

at the finish of the return movement of the disk impinges on a spring'pawl 27 which normally prevents any return movement of the wheel 1 and holds this pawl clear of v the wheel 1, which is therefore returned to its zero position by its spring 8 whereupon the projection 24 is caused'by the spring 25 to reenter the slot 23 and the disk is again locked to the wheel. At the beginning of anothery call the wheel and disk are again rotated together and the rod 26 moves forward alv lowing the pawl 27 to come into operation.

When therefore a call is set up by means of the keys the wheel 1 has the corresponding pins projecting and retracted, and the impulse spring jack 17 has rotated with it.

In orderto release the clutch and pass the call through to the line a lever B (Figs. 1 and 2) is depressed although this. movement can be brought about if desired by attach ing an additional lever 28 to the fork switch hook and thus making the release automatic upon lifting the telephone. This raises a rod 29 which is guided by a pin 291, on the frame so that an incline 292 on the rod presses laterally on the cross piece 18 compressing the spring 25, removing the piece 24 out of the slot 23 and thus releasing the disk which is rotated back by its spring. In so doing the tip 30 of the impulse spring 31 meeting the different pins in turn operates the impulse springs and thus transmits the required impulses to the line.

In order to prevent th pins in the wheel 1 operating the impulse springs as'the wheel returns to its normal position the tip 30 of I the spring 31 is hinged so that it turns about .its pivot and does not operate the impulse springs, but while the disk moves back the tip does not turn on it's hinge and the spring is therefore actuated as required.

' If it is desired to prepare the wheel not by keys but by other operated devices such as finger holds I connect to a dial or the like having in it ten finger holdsa lever carrying a driving pawl and a sliding plate adapted to push back the pins where spaces are tobe formed. This alternative method of driving the mechanism is shown in Figs.-

9, 10 and '11; In this formthe axle? is mounted in a vertical position-and on this axle 7 is an arm 32 carrying a spring controlled driving pawl. 33 and a hinged plate 34. 'In the position of rest the pawl 33 lies against a stop 35 which keeps it out of engagement with the teeth of the wheel 1. On

the plate 34 is a hook 36 which at thecoma curved finger plate 38, which is fast with it and into holes in which the thumb can be inserted and then drawn up to a fixed stop 39, on the far side of which the fore finger can be placed. The wheel 1 is thus rotated through the required angle as in the former case, the only difference being that the space of three pins is formed at the be ginning of each digit instead of at the end. As soon as the hook 36 has cleared the incline 37 the plate 3l is returned by its spring to its normal position clear of the pins. As the arm returns the'hook moves back along the upper face of the incline 37 which turns slightly on its pivot so that the plate is not actuated. \Vhen the required number has been set up the disk is unclutched from the wheel by a rod or lever l0 similar to the rod 29.

Figs. 12 and 1,3 show a dial which can be employed to rotate the arm 32. It is provided with thetenholes for the insertion of a finger and has to be rotated clockwise for each digit. At the front of each hole is pivoted a right angled catch 41 which is normally prevented from rotating on its pivot by a stop l2 carried by the casing 43. IV hen, however, the finger is inserted into any hole and the dial is rotated the catch is carried past its stop 12 and then turns on its pivot under the pressure of the finger so that its shorter arm lies in the path of the stop a2 beyond the next hole, which stop arrests the movement of the dial so that in order to set up any digit the dial is only moved until the hole corresponding to that digit reaches a position just beyond the normal position of the next hole, for instance,

3 moves just beyond the normal position of I dial instead of pullingit, and to obviate this I may arrange these three holes at a smaller distance from the center as shown in dots.

What I claim is 1. In a self-contained impulse-sending apparatus the combination of a plurality of finger-operated devices, a single displaceable member, recording mechanism carried by that member, mechanical means whereby each operation of the finger devices displaces the displaceable member through a definite distance and sets part of the record ing mechanism, means whereby after all the required finger devices have beenoperated electrical impulses are transmitted according to the record set and means for returning the member to its normal position.

In a self-contained impulse-sending apparatus the combination of a plurality of finger-operated devices, a single rotatable member, recording mechanism carried by that .member, mechanical means whereby each operation of the finger devices rotates the member through a definite distance and sets part of the recording mechanism, means whereby after all the required finger devices have been operated electrical impulses are transmitted according to the record set, and means for returning the member to its nor mal position.

3. In a self-contained impulse-sending apparatus the combination of a plurality of finger-operatedv devices, a single displace able member, recording mechanism carried by that member, ratchet mechanism whereby each operation of thefinger devices displaces the displaceable member through a definite distance, mechanism adapted. to set part of the recording mechanism, means whereby after all the required finger devices have been operated electrical impulses are transmitted according to the record set and means for returning the member to its normal position.

I. In a self-contained impulse-sending apparatus the combi'nation of a plurality of finger-operated devices, a rotatable wheel, a series of pins arranged in a circle on the wheel, ratchet mechanism actuatedby the finger devices and adapted to rotate the wheel through an angle dependent on the particular finger device operated, means for retracting a certain number of pins whenever a finger device is operated, a spring adapted to return the wheel to its normal position, means for retaining the'pins retracted until such return movement of the wheel and means actuated by the pins after all the desired finger devices have been operated and adapted to transmit electrical impulses.

5. In a. self-contained impulse-sending apparatus the. combination of a plurality of finger'operated devices, a rotatable wheel, a series of pins arranged in a circle on the wheel, ratchet mechanism actuated by the finger devices and adapted to rotate the wheel through an angle dependent on the particular finger device operated, means for retracting a certain nun'iber of pins whenever a finger device is operated, a member rotatable co-axially with the wheel, means for causing the member to rotate with the wheel while'the latter is rotated by the ratchet mechanism, means for temporarily Wheel and means for returning the Wheel hglding the wheel hstationalgy, a spring to its normal position. a apted to rotate t e mem er ackwar While the Wheel is held stationary, means WILLIAM AITI-{EN' 5 carried by the member and. adapted to be Witnesses:

actuated by the pins for transmitting elec- H. D. JAMESON,

trical impulses, means for releasing the O. J. WORTH. 

